Max volmek



Patented Mar. 29 1932 barren STATE; PATENT orrica m VOLMEB, F IBERLIN-NE'UBABELSEEBG, GERMANY PROCESS OF RECORDING ELECTRIC mPULSES No Drawing. Application filed Indy 7, 1930, Serial No. 466,855, and in Germany July- 8, 1929.

'My invention relates to improvements in the process ofrecording electric impulses, formy invention consists in precipitating, by the said electro-chemica-l action, a substance which does not by itself act as the colouring medium but which has theaction of a catalyst in areaction producing a dyestufi or another precipitate. Therefore by the said current impulses only slight traces of a substance are precipitatedswhich act as a catalyst for the chemical reaction producing the dyestufl or other precipitate at the part of the recording surface where the catalyst has first been produced.

In processes heretofore in use at the most suchv an amount of colouring substance has been generated which corresponds to the current equivalent. But in my improved process the thousandfold amount andmore of the current equivalent is generated by a chemical process which is affected, by catalytic action, by the primaryproducts of the precipitation by the electric current impulse. Therefore it is suificient to produce traces of the catalyst by means of minute amounts of electric en I ergy. which ordinarily are not visible or hard- 3 ly visible, and which start the chemical reaction producing the actual record.

As an example for carryingout my improved process, I proceed as follows The sur- I face such aspaper on which the record is to 40 be made is impregnated with a silver salt and moistened. The electrodes are disposed in any. known or preferred manner. Preferably the electrodeffor producing the record is made from carbon or graphite. By the current impulses silver is precipitated, and the said amount may be so slight, that it is not visible at all. Thereafter the pa er is dipped into a solution of a reducing me ium such as a photographic developing medium, which may contain a little silver salt. Onthe silver ,mium. Further, sulphur metals of conduc-- deposits primarily precipitated further silver is deposited, so that the primary impression is made visible. Thus for example 1000 points per second can be drawn by means of a voltage of a little less than 1 volt and a current intensity of a few millionths of an am-- pere. If it is not desired to work in the dark I use a silver salt which is-not sensitive to light, such as the nitrate, or I remove the sensibility. to light by means of a known or preferred desensibili'zing medium such as plcric acid. .In lieu of the silver other metals may be used such as platinum, gold, copper, mercury, etc., and to the salts of the said metals alkali salts maybe added. The substances needed for the secondary reaction may be contained in the wet paper, so that the sec ondary reaction takes place immediately after the impulse has been transmitted to the paper, and the record is immediately made visible. Since the colouring substance, in the example referred to'the silver, is not sensitive to heat, the apparatus may be arranged so that immediately dry records .areproduced. a 1

In the practical operation of the process I have found that not all the materials heretofore used for manufacturing electrodes are suitable in my improved process. Some metal electrodes leave traces of the metal on the paper which by themselves have catalytic action on the secondary reaction. In the new process particularly recording electrodes are suitable, which are made from particularly hard substances which are not adapted to produce nuclei. I have found that recordmg electrodes of great hardness and conductiv-- ity are suitable which consist of carbon, siliy con, selenium, antimony, tungsten, osmium, aridium, platinum-irldlum and platinum-0s:

'tive property may be used, and I have found that the particles which may be rubbedtherefrom are not injurious, because they have no catalytic action. 7 I

. The carbon, silicon, selenium, and antimony 'must not .necessarily. be used in the form of solid bodies, but they may be used in the form of coatings applied .to. carriers of suitable shape a 'similar way as such scratches are noticed on the sensitized photographic plate. Further, the said form of carbonhas a high chemical indifference.

I claim:

1. The rocess of producing a record of an electrical impulse which includes the follow-- ing'steps': precipitating by electro-chemical action a substance on an electrolytically conductive surface, and utilizing said substance thereafter as a catalyst to initiate a secondary chemical reaction.

2. The method of producing a record of an electrical impulse which consists in the following steps: impregnating a paper surface with a metallic salt,m0istenin said surface,

8. The process of claim 1, in which the electrolytic precipitation is accomplished by the use of electrodes formed in relatively thin coatings upon a suitable conductive carrier and in which the electrodes are of such nature that they leave-no traces upon the material upon which the precipitation has occurred.

Signed at Berlin, Germany, this 26th day of June 1930.

- MAX VOLMER.

precipitating the metal by electric impulse,

thereafter bringing the paper into contact with a solution of the metallic salt, whereby the metal already precipitated on the paper acts as a catalyst to initiate the further deposition of the metal from the solution upon the already precipitated metal upon the paper.

3. The process according to claim 1, in which a reducing medium is used and in which the substance used is a metallic salt which acts as a catalyst in connection with the reducing medium;

4. The process of claim 1, in which a reducing medium is used and in which the preci itated substance is a metallic salt, the uci ng medium being added to the surface after the electrolytic precipitationhas occurred.

' 5. The process of claim'l, in which the substance which is electrically precipitated by electro-chemical action is a metallic salt and in which an additional metallic salt is added by a reducin medium after the initial electrolytic precipitation.

6. The process of claiin 1, in which a reducing medium containing a silver salt is added after the electrolytic precipitation and in which the substance electrolytically pre cip'itated is a silver salt which is not sensi-'- tive to light at the time of the addition to it of the reducing medium 7 7. The process ofclaim 1, in which the electrolytic precipitation is accomplished by the use of electrodes ofsuch nature that the leave no traces upon the material upon which the precipitation has 

